A chain-of-custody approach for allocating input characteristics to outputs within defined rules.
In a mass-balance system, documented inputs and outputs are reconciled over specified boundaries so a claim can be allocated under the relevant scheme. The claim needs the scheme rules, boundary and accounting evidence beside it. An allocation is not itself a measurement of the physical contents of each individual item.
Mass balance is a chain-of-custody approach whose allocation and reconciliation rules depend on the governing scheme, not a claim of physical identity.
No uninspected ISO-clause quotation or unsupported five-model list.
Public ISO abstracts describe ISO 22095:2020 as a general chain-of-custody framework and ISO 22095-2:2026 as mass-balance-specific. Scheme rules, not the abstract alone, govern a particular claim.
Source-grounded explanatory term, not a formal definition in the cited provisions. Source context is paraphrased, not quoted legal text.
Preserve the claim scheme, eligible inputs, output allocation, time/geographic boundary and reconciliation evidence.
Any allocation claim needs its named scheme, reconciliation period and evidence trail; public ISO abstracts do not settle those rules.